Excavations beneath the modern city of York have revealed a secure cellar that once served as a Roman Intelligence Bureau (Frumentarii). Within the room, archaeologists found several 'stilus' tablets—wood frames filled with wax—containing what appear to be encrypted military dispatches. Early analysis suggests the use of a simple substitution cipher, used to communicate troop movements and security threats along the northern frontier of Roman Britain.
The bureau was located near the legionary fortress but was structurally isolated, featuring thick stone walls and a single, heavily reinforced entrance. The recovery of bronze stylus pens and iron lock mechanisms confirms the highly secretive nature of the office. This is the first time a dedicated space for military intelligence has been identified in a Roman provincial capital.